1. Field of the Invention
The present invention relates to driving of pixel display devices, and in particular, the generation of interlaced images for supply to autostereoscopic display devices comprising an array of display pixels arranged in rows and columns, and an array of elongate lenticular elements extending parallel to one another overlying the display pixel array and through which the display pixels are viewed.
2. Description of the Related Art
Examples of such autostereoscopic display apparatus are described in the paper entitled xe2x80x9c3-D Displays for Video telephone Applicationsxe2x80x9d by D. Sheat et al in Eurodisplay 1993 and in UK Patent Application GB-A-2196166. In these apparatuses, the display is produced by a matrix display device comprising a matrix LC (liquid crystal) display panel having a row and column array of display elements and acting as a spatial light modulator. The lenticular elements are provided by a lenticular sheet, whose lenticules, comprising (semi) cylindrical lens elements, extend in the column direction of the display panel with each lenticule overlying a respective group of two, or more, adjacent columns of display elements and extending parallel with the display element columns. Commonly in such apparatus, the LC matrix display panel is of a conventional form, comprising regularly spaced rows and columns of display elements, as used in other types of display applications, e.g., computer display screens, although other arrangements may be provided.
Considering a direct-view type of apparatus, then the display pixels forming the display are constituted by the display elements of the display panel. In an arrangement in which each lenticule is associated with two columns of display elements, the display elements in each column provide a vertical slice of a respective 2D (sub-)image. The lenticular sheet directs these two slices and corresponding slices from the display element columns associated with the other lenticules, to the left and right eyes, respectively, of a viewer in front of the sheet so that the viewer perceives a single stereoscopic image. In other, multi-view, arrangements, in which each lenticule is associated with a group of four, or more, adjacent display elements in the row direction, and in which corresponding columns of display elements in each group are arranged appropriately to provide a vertical slice from a respective 2-D (sub-) image, then as a viewer moves his or her head, a series of successive, different, stereoscopic views are perceived creating, for example, a look-around impression.
In the design of such systems, the pitch of the lenticular array depends on the pixel pitch of the screen it is to be applied to, and will generally be given in terms of integer multiples of the pixel pitch reduced by a fraction that depends on the intended magnification of the pixels at the required viewing distance. This is true for both conventional screen arrangements (as above) with the lenticules running vertically, and also for arrangements (as will be described herein) with the lenticules running at an angle to the vertical. Such a constraint places unacceptable limits on both the manufacturing process and operational capability for these devices.
It is an object of the present invention to provide a means for adapting a pixel display to an applied lenticular screen in forming an autostereoscopic display apparatus.
It is a further object to enable the reconfiguration of existing two-dimensional pixel displays to autostereoscopic displays when a lenticular array is applied.
According to a first aspect of the present invention, there is provided a method for controlling pixel addressing of a pixel display device to drive the display device as an N-view, autostereoscopic display when a lenticular screen is overlaid and image pixel data for N discrete views to be interlaced is provided, the method comprising the steps of: obtaining data defining at least the lenticular screen. lenticule pitch, the number of views N, and the lenticular screen position relative to the display device pixels; applying a predetermined algorithm to derive, from the obtained data and for each display pixel, which of the N views it is to carry; and, for each display pixel, extracting the corresponding pixel data for the assigned view from the data provided. By deriving which of the N views each display pixel is to carry, by reference to parameters of the lenticular screen, and driving the display accordingly, the requirement for the lenticular to be tied to a particular display device is removed. This, in turn, enables the reconfiguration of existing displays, for which no specific lenticular array has been constructed, to accept a lenticular array and thus provide an autostereoscopic output.
In accordance with a further aspect of the present invention, there is provided a display configuration utility carried on a removable record carrier and for reading by means for controlling display driver circuitry of a pixel display, the utility, when run, controlling pixel addressing to drive the display device as an N-view autostereoscopic display when a lenticular screen is overlaid and image pixel data for N discrete views to be interlaced is provided, the utility effecting the steps of: obtaining data defining at least the lenticular screen lenticule pitch, the number of views N, and the lenticular screen position relative to the display device pixels; deriving, from the obtained data and for each display pixel, which of the N views it is to carry; and, for each display pixel, extracting the corresponding: pixel data for the assigned view from the data provided.
The configuration utility, which may be supplied to a user as a package with a lenticular screen and/or multiple view image data, may be operable to generate one or more predetermined display images in the form of a menu specifying data required to be input by a user, in order to enhance the xe2x80x9cuser-friendlinessxe2x80x9d of the reconfiguration operation. The data required to be input may include an angle of offset between the pixel column direction and the principal axis of a screen lenticule and/or an offset in the pixel row direction to enable the user to line up the generated views as desired. In a partial automation of the procedure, the configuration utility may comprise means operable to determine required data specifying parameters of the pixel display device from the display driver. Alternatively, the configuration utility may further comprise a plurality of data files each holding the required data for a different predetermined type of display device and/or lenticular array, together with means for generating a user-selectable menu of said types.
In accordance with a still further aspect of the present invention, there is provided a driver apparatus operable to generate a per-pixel drive signal for output to a pixel display device, said apparatus comprising an image data store coupled with display image formatting means, said formatting means being operable to extract per-pixel data from the store and format said drive signal; characterized in that said apparatus is reconfigurable to drive the display device as an N-view autostereoscopic display when a lenticular screen is overlaid, said image data store holding pixel data for N views to be interlaced, and the formatting means having an input to receive data identifying the lenticule pitch and position relative to the display device pixels and being operable to derive, for each display pixel, which of the N views it is to carry and to extract the corresponding pixel data for that view from the data store. Such an apparatus may suitably further comprise user data input means, and means for generating one or more display screens to appear on the display and indicating data required to be input by the user. Also, to assist in the installation procedure for a particular lenticular, the apparatus may further comprise means for generating one or more predetermined test screens to appear on the display, said test screens being such as to indicate to the user the effect of variation of one or more input parameters, such as the above-referenced horizontal offset.
Further features and advantages of the present invention will become apparent from reading of the following description of embodiments of the present invention, which description details the derivation of the required view per pixel.